textproduct: Albany

WHAT HAS CHANGED

Max temps were lowered this afternoon below the NBM values by 3-4 degrees with the rain cooled air due to the approaching wave and warm front.

Moderate to heavy rainfall from the warm front and the wave continues to be this afternoon and prior to midnight with hourly rainfall up to or around an inch an hour possible, and the consensus to a slightly more northern track continues.

Some showers may linger Tue morning across western New England and from the Capital District south and east with the mid and upper deformation zone to the wave. In the wake of the system Tue, some patchy valley fog was added mainly north of the Capital Region.

KEY MESSAGES

1) High confidence for a widespread soaking rainfall across eastern NY/western New England today into tonight. This will be a largely beneficial rainfall for most areas, although isolated minor flooding in urban/poor drainage areas is possible.

2) After a dry mid week, temps rise slightly above normal with increasing humidity levels with chances of showers and thunderstorms increasing late Thu through Fri.

DISCUSSION

KEY MESSAGE 1... Low pressure approaches from the Ohio Valley and the Lower Great lakes Region this morning. A closed H500 low is moving across southeast Ontario into Quebec. The sfc low and its warm front will cause clouds to thicken and lower this morning, as morning valley mist/fog in the Lake George/Glens Falls area, southern VT valleys and Berkshires burns off. The low-level jet will increase ahead of the warm front with PWATS rising into the 1.25-1.75" range across the forecast area with the highest values around 1.75" south and east of the Capital District. These PWATS are 1-2 STDEVs above normal according the latest NAEFS. Isentropic lift increases ahead of the warm front and approaching cyclone with favorable mid and upper level jet dynamics /right entrance region of the jet/ in tandem with strong FGEN in the 850-700 hPa layer moving over central- eastern NY and western New England in the afternoon into the early evening 18Z-00Z/Tue timeframe. Strong moisture advection occurs with periods of moderate to locally heavy rain to occur. The latest HREFs indicate mean MUCAPEs of 100-250 J/kg from the Capital Region, southern VT and northern Catskills southward this afternoon into early tonight. Some pockets in the 250-500 J/kg range are closer to I-84. The 0-6 km shear increases to 35-50 KT towards 00Z/Tue, but with elevated parcels and limited instability the severe threat seems low due to limited instability, though the wave moving a but further north like the NAM, 3-km HRRR and CMC might allow the mid Hudson Valley to get into a warm sector briefly. SPC continues a Marginal Risk (Level 1 of 5) for the southern 3 counties (Ulster...Dutchess...and Litchfield Counties) with damaging winds the main threat. We did include slight to low chances of thunderstorms as far north as the Mohawk Valley, Capital District and southern VT.

The biggest impact with this system would be the rainfall and enhanced rainfall rates, which are supported by the 3-km HRRR. Some hourly rates could reach or slightly exceed an inch per hour. The 3-km HRRR shows high probs of 0.25-0.50"/hr as far north as the Capital District and southern VT. The latest NBM indicates probabilities of 60-90% that 24-hr rainfall amounts could exceed one inch by 12Z/8 am Tue for most of the forecast area, except for the southern Dacks. In fact the maximum probs have shifted north over the Capital Region and southern VT. The probabilities for >2" are 20-50%. Our forecast supported the latest NBM/WPC forecast with 1-1.50" of rainfall for the event with some 1.50-2.0" amounts over the southern VT and the southern Taconics, Berkshires and NW CT. Expect a half an inch to an inch over the southern Dacks. The amounts will vary where the heavier showers and thunderstorms set up and some localized amounts of 2-3" are possible.

The Marginal Risk continues over most of the forecast area, except the southwest Adirondacks. An isolated flash flood can not be ruled out if rainfall rates becomes excessive or storms train or back build briefly. Ponding of water and poor drainage flooding is likely. The rainfall will be beneficial, as many areas along and south of I-90 are in D0 (Abnormally Dry) to D1 (Moderate Drought) based on the latest Drought monitor. The rainfall eases up after midnight, but lingers south and east of the Capital Region into western New England into mid to late Tue morning with residual mid and upper deformation support. Temps this afternoon will run cooler than normal with the clouds and rain cooled air with highs only in the 60s to lower 70s with some. We went below the NBM guidance by 3-4 degrees and closer to a MAV/MET blend. In the wake of the system, lows fall back into the 50s to lower 60s.

KEY MESSAGE 2... High pressure builds in late Tue through Wed. Temps will remain seasonable for the mid week. Some patchy to areas of fog may form in some of the major valleys Tue night especially north of the Capital District. Temps trend near normal on Wed with 70s to lower 80s (some upper 60s over the higher terrain) with comfortable humidity levels.

The timing varies on the next system for Thu into Fri, as a short-wave and a low pressure system approaches from the Great Lakes Region and southeast Ontario for Thu. The better chance for showers and thunderstorms on Thu will be from the Hudson River Valley westward. Chances of showers and thunderstorms increase Thu night into Fri ahead of the wave and cold front. We will continue to monitor if any thunderstorms will be on the strong side by Friday with dewpoints rising into the mid and upper 60s and increasing humidity levels. The degree/amount of instability remains uncertain late in the week. Temps Thu and Fri will be range from the 70s to lower/mid 80s which are slightly above normal for early summer for eastern NY and western New England.

AVIATION /06Z MONDAY THROUGH FRIDAY/

Through 06Z Tuesday... MVFR/IFR radiational mist/fog will likely continue at KGFL prior to 09Z-10Z before thicker cirrus begins to move in. A TEMPO was used between 06Z-09Z/Mon for KPSF for a brief window of IFR radiational mist/fog too. Mid and high clouds quickly move in between 09Z-15Z/Mon at the TAF sites. Clouds gradually lower across all terminals prior to 15Z/MON. Initial batch of light rain/showers moves in between 15Z-18Z/MON with VFR cigs/vsbys lowering to high MVFR levels between 18Z-20Z/MON and spotty IFR levels. The rain becomes steadier and heavier after 20Z/Mon and widespread low MVFR/IFR conditions will impact all the TAF sites. A thunderstorm with a TEMPO group was added to KPOU between 20Z/Mon and 00Z/Tue. It may have to be extended past 00Z/Tue with later TAF issuances. Our confidence was lower for thunderstorms further northward and we left out of the TAFs for now at KALB/KPSF/KPSF. Widespread IFR and even some LIFR conditions in terms of cigs may develop after 00Z/Tue in the deep moisture as the wave approaches southern NY and passes to the south and east overnight. Occasional showers continue until the end of the TAF cycle.

Calm to light and variable winds 4 KT or less across all terminals prior to 12Z/Mon. Southeast to southerly winds in the 5-10 KT range increase in the late morning. The winds become northeast in the afternoon into the evening at less than 10 KT at KALB/KGFL with southeast to east winds at KPSF/KPOU at 4-8 KT. Low-level wind shear was added for KPOU/KPSF after 00Z/Tue, where winds at 2 kft AGL increase to 35-40 KT, and the sfc winds are less than 10 KT.

Outlook...

Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: Moderate Operational Impact. Chance of SHRA...TSRA. Thursday Night: High Operational Impact. Definite SHRA...TSRA. Friday: High Operational Impact. Likely SHRA...TSRA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.